The present invention relates to a process for producing artificial leather, which looks and feels exactly the same as real tanned leather, using as raw material one of the many synthetic sheet materials known and marketed under various trade names and commonly referred to as "imitation leather". In particular, the present invention relates to a chemical process particularly suitable for synthetic sheet material comprising a porous polyurethane resin matrix, the latter embedded with polyester or polyethylene strengthening fibres, and a compact, pressed polyurethane resin cover film patterned to imitate real leather.
Various synthetic sheet materials are known, made from polymer resins and designed to imitate and replace various types of real leather for a wide range of applications, e.g. for upholstery, shoes, clothing and similar. The said synthetic sheet materials are usually made using two layers of polyurethane resin placed one on top of the other, the bottom one of which is foamed so as to produce a porous matrix (open- or closed-cell, depending on the type of manufacturing process employed) designed to afford consistency and thickness to the said sheet material, whereas the top layer is compact, usually coated on and pressed with a pattern imitating real leather. Of known materials, the best, and the one most closely resembling real leather in terms of consistency and appearance, is a material of the aforementioned type, i.e. formed of polyurethane resin layers and comprising a porous, open-cell matrix embedded and polyester or polyethylene fibres allowed to move essentially freely along their axes inside the said matrix. A section of such a material is shown in the microphoto in FIG. 1, the said material being made and marketed by the Japanese firm "KURARAY CO. Ltd", 1-12-39 Umeda, Kita-ku, OSHAKA 530 (Japan).
A major drawback of known materials of the aforementioned type is that they are highly inflammable and therefore require the addition of fireproofing substances. In addition to being impaired drastically in appearance, to such an extent as to be rendered unusable for a wide range of applications, the look, feel and consistency of the said materials is highly unsatisfactory and still far from competing with the appearance and consistency of real leather.